Method of operating a capacitive proximity sensor and capacitive proximity sensor

US10197377B2 · kind B2 · utility

Assignee

• Brose Fahrzeugteile GmbH & Co. Kommanditgesellschaft, Hallstadt · DE

Inventors

• Florian Pohl · Ebersdorf, DE
• Holger Wuerstlein · Zeil am Main, DE
• Christoph Brand · Bad Königshofen im Grabfeld, DE

Key dates

• Filing date: Jul 23, 2015
• Grant date: Feb 5, 2019
• Expiry date: Aug 30, 2037

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03K2217/960775
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

During operation of a capacitive proximity sensor that is provided with at least two measuring electrodes, a first capacitance measurement variable and a second capacitance measurement variable are detected. The first capacitance measurement variable is correlated with the capacitance of at least one of the measuring electrodes to earth, while the second capacitance measurement variable is correlated with the capacitance between at least one of the measuring electrodes and at least one further measuring electrode. A change in the first capacitance measurement variable is evaluated together with a synchronous signal profile of the second capacitance measurement variable in order to distinguish a proximity of a conductor coupled electrically to earth from the proximity of dielectric matter. In this manner, a body part passing into the detection space of the proximity sensor can be distinguished effectively from other substances and objects, particularly water.